Aqueous dispersions

ABSTRACT

The invention concerns hydrous compositions based on polychloroprene and hydroxylamine derivatives, processes for their production and their use as adhesives. The polychloroprene dispersions are stabilized by the addition of hydroxyalkylamine after removal of residual monomer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 (a)-(d) to Germanapplication DE 102006001942, filed Jan. 14, 2006.

FIELD OF THE INVENTION

The invention concerns water-containing compositions, in particularaqueous polymer dispersions based on polychloroprene and hydroxylaminederivatives, processes for their production and their use, in particularfor the production of sealants and coatings, in particular for theproduction of adhesive coatings, and a process for bonding together thesubstrates coated on one or both sides with the compositions.

BACKGROUND OF THE INVENTION

Contact adhesives based on polychloroprene (CR) are predominantlysolvent-containing adhesives that are applied to substrates to be bondedtogether and are dried. By subsequently joining the substrates togetherunder application of pressure, a joint structure is obtained with highinitial strength immediately after the joining process.

For ecological reasons there is a growing need for suitable aqueous CRadhesive dispersions that can be processed to obtain correspondingaqueous CR adhesive formulations. These are used in the spray-mixprocess, for example, in which the aqueous adhesive formulation and acoagulant are conveyed separately in a spray gun and finally mixed inthe spray jet, whereupon the CR adhesive coagulates on the substrate. Anoverview of this method can be found for example in “Handbook ofAdhesives”, Irving Skeist, Chapman, Hall, New York, 3^(rd) Edition,1990, Part 15, page 301; R. Musch et al., Adhesives Age, January 2001,page 17, “Spray-Mixing Klebstoffe auf Basis Dispercoll® C für dieSchaumstoff-Klebung”, Technical Information from Bayer AG, no.KA-KR-0001d/01/05.96.

It is often necessary, however, for additives such as stabilisers and/orantioxidants, for example, to be added to the aqueous CR dispersions orformulations in order to give them an appropriate storage stability andsafety in use or to protect the adhesive coatings from ageing ordiscoloration.

For the latter purpose aqueous formulations are advantageously mixedwith zinc oxide, since in formulations based on polychloroprenedispersions it counteracts rapid ageing of the glueline anddiscoloration of the bonded substrates due to the release of HCl fromthe CR polymer.

Antioxidants are also added, preferably based on oligofunctionalsecondary aromatic amines or oligofunctional substituted phenols such asproducts of the type 6-PPD (N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine; Vulkanox®, Lanxess Deutschland GmbH), DTPD, DDA, BPH, BHT,etc., as described for example in Handbuch für die Gummiindustrie, 1992edition, Bayer AG, Leverkusen, chapter 4, Vulkanox®, p. 423. Vulkanox®DDA, a diphenylamine derivative, is particularly effective.

The zinc oxide dispersions known to date have a tendency to settle,however. This settling or phase separation is not acceptable,particularly where such adhesive formulations are used in the spray-mixprocess, because it causes the nozzle to clog. Cleaning the nozzle istime-consuming and cost-intensive and is unsatisfactory from an economicviewpoint.

The organic antioxidants in turn are either not resistant todiscoloration (oligofunctional secondary aromatic amines) or are lesseffective (oligofunctional substituted phenols).

The object of the present invention was to provide novel aqueouspolychloroprene dispersions and adhesive compositions which are freefrom residual monomer and are stable in storage and which, afterapplication to the substrates to be bonded and joining, have a highresistance to HCl release from the polymer.

SUMMARY OF THE INVENTION

It was found that the stabilisation of aqueous polychloroprenedispersions and preparations can be improved markedly by the addition ofhydroxylamine and derivatives thereof. Either hydroxylamines are addedin addition to the previously used antioxidants or the conventionalantioxidants are partially or wholly replaced by hydroxylamines.Hydroxylamines stabilise polychloroprene dispersions by trapping HCl,which can be released from the polychloroprene, and act as antioxidantsby stopping radical reactions in the dry films produced from the aqueouspreparations. An additional stabilisation can be achieved through theuse of nano zinc oxide, allowing the problem of settling of zinc oxidedispersions corresponding to the current prior art to be eliminated.Furthermore, nano silicon dioxide dispersions also have a stabilisingeffect on resistance to HCl release and discoloration in the dry filmsproduced from the aqueous preparations.

The present invention therefore provides a composition containing:

-   A) polychloroprene particles,-   B) hydroxylamines having the general formula (I),

wherein

-   R¹ and R² mutually independently stand for hydrogen (H), linear or    branched, saturated or unsaturated, unsubstituted, monosubstituted    or polysubstituted C₁ to C₂₀ alkyl radicals or C₆ to C₁₂ aryl    radicals or C₇ to C₁₄ aralkyl radicals or C₅ to C₇ cycloalkyl    radicals or R¹ and R² are joined together by an unsubstituted,    monosubstituted or polysubstituted C₃ to C₇ cycloalkyl radical and-   C) water.

The composition is in the form of an aqueous dispersion in particular.

DETAILED DESCRIPTION OF THE INVENTION

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about”, even if the term does notexpressly appear. Also, any numerical range recited herein is intendedto include all sub-ranges subsumed therein.

Polychloroprene particles within the meaning of the invention areparticles of polychloroprene (poly-(2-chloro-1,3-butadiene) and ofcopolymers containing chloroprene.

The polychloroprene (poly-(2-chloro-1,3-butadiene) particles areconveniently added to the composition according to the invention in theform of aqueous dispersions. The production of such polychloroprenedispersions is known per se and takes place by emulsion polymerisationin an alkaline aqueous medium, see “Ullmanns Encyclopädie dertechnischen Chemie”, Volume 13, p. 614, Verlag Chemie, Weinheim, N.Y.;4^(th) Edition 1977; “Encyclopedia of Polymer Science and Technology”,Vol. 3, p. 705-730, John Wiley, New York 1965; “Methoden der OrganischenChemie” (Houben-Weyl) XIV/1, 733 ff. Georg Thieme Verlag Stuttgart 1961.

Polychloroprene dispersions that are produced by continuouspolymerisation are particularly preferred, as described for example inWO 02/24825, example 2, and DE-A 3 002 734, example 6, wherein theregulator content can be varied between 0.01 wt. % and 0.5 wt. %.

Suitable copolymerisable monomers are preferably compounds having 3 to12 C atoms and 1 or 2 copolymerisable C═C double bonds per molecule.Examples of preferred copolymerisable monomers are 2,3-dichlorobutadieneand 1-chlorobutadiene.

The polychloroprene dispersion for use in the process according to theinvention is produced by emulsion polymerisation at 0 to 70° C.,preferably at 5 to 45° C., and at pH values of 10 to 14, preferably pH11 to pH 13. Activation is carried out with the conventional activatorsor activator systems.

The following can be cited as examples of activators or activatorsystems: formamidine sulfinic acid, potassium peroxodisulfate, redoxsystems based on potassium peroxodisulfate and optionally a silver salt,the Na salt of anthraquinone-β-sulfonic acid, wherein compounds such ase.g. formamidine sulfinic acid, the Na salt of hydroxymethane sulfinicacid, sodium sulfite and sodium dithionite serve as redox partners.Redox systems based on peroxides and hydroperoxides are also suitable.The polychloroprenes according to the invention can be produced bothcontinuously and batchwise, continuous polymerisation being preferred.

To adjust the viscosity of the polychloroprenes according to theinvention, conventional chain transfer agents can be used, such asmercaptans, as described for example in DE-A 3 002 711, GB-A 1 048 235,FR-A 2 073 106, or such as xanthogen disulfides, as described forexample in DE-A 1 186 215, in DE-A 2 156 453, DE-A 2 306 610 and DE-A 3044 811, in EP-A 0 053 319, in GB-A 512 458 and GB-A 952 156 and in U.S.Pat. No. 2,321,693 and U.S. Pat. No. 2,567,117.

The polymerisation is conventionally terminated at 50% to 95%,preferably at 60% to 80% of the monomer conversion, wherein for examplephenothiazine, tertbutyl pyrocatechol or diethyl hydroxylamine can beadded as inhibitors.

In the described radical emulsion polymerisation the monomer isincorporated in the polymer chain in various configurations, namely inthe trans-1,4 and cis-1,4 position, in the 1,2 position and in the 3,4position, see: “W. Obrecht in Houben-Weyl: Methoden der organischenChemie Vol. 20 Part 3 Makromolekulare Stoffe (1987) p. 845”, the monomerincorporated in the 1,2 position containing an unstable, easilyseparable chlorine atom that is responsible for HCl release from thepolymer.

Following polymerisation the remaining monomeric chloroprene is removedby steam distillation and a residual monomer-free dispersion isproduced. Steam distillation is performed as described for example in“W. Obrecht in Houben-Weyl: Methoden der organischen Chemie Vol. 20 Part3 Makromolekulare Stoffe (1987) p. 852”. Through repeated steamdistillation, the content of monomeric chloroprene in the polymer can bereduced to values of around 100 ppm, preferably 50 ppm or less. Suchdispersions are classed as residual monomer-free dispersions within themeaning of the present invention. During this process, however, thestopper diethyl hydroxylamine still present in the dispersion from thepolymerisation stage is removed, such that its content in the latex isbelow the detection limit of >1 ppm.

The use of hydroxylamines as polymerisation inhibitors, i.e. to stoppolymerisation, either alone or in combination with other stoppers, isdescribed for example in “Methoden der Organischen Chemie” (Houben-Weyl)XIV/1, p. 435, 441, 746 ff. Georg Thieme Verlag Stuttgart 1961.

The effectiveness of certain hydroxylamines in suppressing thephenomenon known as popcorn formation during polymerisation is alsodescribed.

The stabilising effect according to the invention is no longer presentin the finished, residual monomer-free polymer dispersion, however,because—as mentioned above—the described hydroxylamines are removedalong with the residual monomer, which for toxicological reasons isremoved from the latex obtained immediately after the end ofpolymerisation, by steam distillation for example.

The solids content of this low-monomer polychloroprene dispersion can beincreased if necessary in a further step by means of a concentrationstep (creaming process). This creaming takes place for example by theaddition of alginates, as described in “Neoprene Latices, John C. Carl,E.I. Du Pont 1964, p. 13”, or by means of a creaming process using acoalescing agent, as described in DE-A 10 145 097, which is particularlypreferred.

In a preferred embodiment of the invention, the polychloropreneparticles have an average primary particle diameter of less than 220 nm.

Analogous to DIN 53206; 1992-08, the term “primary particle” denotesparticles that are detectable as individuals by means of suitablephysical methods. It is possible to speak of “diameters” in connectionwith the polychloroprene particles as the particles are approximatelyspherical.

The average primary particle diameter of the polychloroprene particlesis preferably determined according to the invention by means ofultracentrifuging, see: H. G. Müller, Progr. Colloid Polym. Sci. 107,180-188 (1997). The weight average is stated.

An average primary particle diameter of more than 220 nm can bedisadvantageous, because undesirable sedimentation can occur duringremoval of the residual monomer 2-chloro-1,3-butadiene from thepolychloroprene dispersion by steam distillation.

In a further preferred embodiment of the invention, the polychloropreneparticles have an average primary particle diameter of more than 60 nm.

An average primary particle size of less than 60 nm can bedisadvantageous, because a concentration of the polymer dispersion to asolids content of >55 wt. % is no longer possible. Thus theconcentration of e.g. styrene butadiene (SBR) latex having a particlesize of 78 nm with ammonium alginate is no longer possible (Ind. Eng.Chem. 43, 407 (1951)).

The polychloroprene particles preferably have an average primaryparticle diameter of 60 to 220 nm, preferably 70 to 160 nm.

The cited average primary particle diameters of the polychloropreneparticles are present both in the aqueous dispersions used to producethe compositions according to the invention and in the compositionsaccording to the invention that are obtained.

The production of the hydroxylamines for use according to the inventionis known and is described for example in “Methoden der OrganischenChemie” (Houben-Weyl) X/1, p. 1097-1279. Georg Thieme Verlag Stuttgart1971.

They correspond to the general formula (I)

wherein

-   R¹ and R² mutually independently stand for hydrogen (H), linear or    branched, saturated or unsaturated, unsubstituted, monosubstituted    or polysubstituted C₁ to C₂₀ alkyl radicals or C₆ to C₁₂ aryl    radicals or C₇ to C₁₄ aralkyl radicals or C₅ to C₇ cycloalkyl    radicals or R¹ and R² are joined together by an unsubstituted,    monosubstituted or polysubstituted C₃ to C₇ cycloalkyl radical.

Suitable hydroxylamines include, for example, aliphatic and aromatichydroxylamines, including those that are N- and O-substituted. Preferredare aliphatic and aromatic low molecular weight hydroxylamines, whichare N-substituted.

Especially preferred are N,N-Diethyl hydroxylamine, N-isopropylhydroxylamine, N,N-Dibenzylhydroxylamine, N,N-dibutylhydroxylamine, andN-tertbutyl hydroxylamine according to the invention.

According to the invention the hydroxylamines are added to the finishedpolychloroprene dispersion alone or in combination with other auxiliarysubstances. The amount to be used depends on the nature of thepolychloroprene dispersion to be protected against ageing and on thedesired intensity of the protective effect and can easily be determinedby the person skilled in the art in this field by means of preliminaryexploratory tests. The hydroxylamines are generally added in aconcentration of 0.05 to 2 wt. %, preferably 0.1 to 1 wt. %, based onsolids. The addition can be made at any time, preferably immediatelyafter production (polymerisation) of the dispersion, or as apost-additive to a finished formulation.

The compositions according to the invention can additionally containnano zinc oxide particles (D1) whose average particle size is less than150 nm, preferably less than 100 nm, particularly preferably less than50 nm. As the nano zinc oxide particles are not spherical, it is moreaccurate to speak of average particle size rather than average particlediameter.

The nano zinc oxide particles (D1) can be present in the compositionsaccording to the invention both as primary particles and in the form ofagglomerates. According to the invention the term “average particle sizeof the ZnO particles” denotes the average particle size determined byultracentrifuging and includes the size of primary particles and of anyagglomerates that may be present (see: H. G. Müller, Progr. ColloidPolym. Sci. 107, 180-188 (1997)). The weight average is specified.

The nano zinc oxide particles are conveniently added to the compositionsaccording to the invention in the form of aqueous ZnO dispersions. Theseaqueous dispersions can additionally contain organic high-boilingsolvents such as triethanolamine or ethylene glycol and/orsurface-modifying compounds. The ZnO particles can consist of eithernon-agglomerated ZnO primary particles or ZnO agglomerates or ofmixtures of dispersed ZnO primary particles and ZnO agglomerates, whosedimensions can be as described above.

The aqueous dispersions of zinc oxide preferably used in the presentinvention to produce the compositions according to the invention can beproduced in various ways. Particularly suitable, however, are processesin which the zinc oxide particles are produced by precipitation from azinc salt solution with alkali and are then processed further to form adispersion. Suitable examples are:

-   I) a zinc oxide sol as described for example in WO 00/50503,    produced by redispersion of zinc oxide gels having an average    primary particle size of <15 nm. Water or water/ethylene glycol    mixtures are suitable as solvents, optionally with the addition of    surface-modifying compounds    or-   II) zinc oxide sols as described for example in WO 02/083797 having    an average primary particle size of <30 nm and an average    agglomerate size of <100 nm, produced for example by the process    described in WO 02/083797.

Just as suitable for producing the compositions according to theinvention are ZnO dispersions produced with surface-modified zincoxides, as described for example in DE-A 10 163 256, for example by oneof the processes described therein.

In a preferred embodiment of the invention, the compositions accordingto the invention contain further additives, such as in particularsilicon dioxide particles (D2). The silicon dioxide particles incombination with zinc oxide lead to an increase in the viscosity of theadhesive dispersion. The combined use of nano zinc oxide (D1) andsilicon dioxide (D2) dispersions is particularly preferred.

The average silicon dioxide particle size or the average diameter of thesilicon dioxide particles (the particles are approximately spherical),determined by ultracentrifuging (as specified above), is preferably inthe range from 1 to 400 nm, more preferably in the range from 5 to 100nm, particularly preferably in the range from 8 to 50 nm. The averagesilicon dioxide particle diameter includes the particle diameter of theprimary particles and of any agglomerates that may be present.

The silicon dioxide particles are preferably added to the compositionsaccording to the invention in the form of aqueous silicon dioxidedispersions having an average particle diameter of the SiO₂ particles of1 to 400 nm, preferably 5 to 100 nm, particularly preferably 8 to 50 nm.

The cited aqueous silicon dioxide dispersions are particularlypreferably added to the compositions according to the invention in theform of hydrous silica sols. The particle sizes of the silica sols usedare not subject to any substantial change during incorporation into thecompositions according to the invention.

Silicon dioxide dispersions that are suitable according to the inventioncan be obtained on the basis of silica sol, silica gel, pyrogenicsilicas or precipitated silicas or mixtures of those cited and aredescribed in DE-A 10 224 898.

It is likewise preferable for the SiO₂ particles to have hydroxyl groupson the particle surface. Aqueous silica sols are particularly preferablyused as aqueous silicon dioxide dispersions.

In a further preferred embodiment of the invention, the compositionsaccording to the invention contain at least one antioxidant that differsfrom the ZnO particles described above. The antioxidant is preferablybased on oligofunctional secondary aromatic amines (D3) and/oroligofunctional substituted phenols (D4), such as products of the type6-PPD, DTPD, DDA, BPH, BHT, etc., as described for example in Handbuchfür die Gummiindustrie, 1992 edition, Bayer AG, Leverkusen, chapter 4:Vulkanox®, p. 423. Vulkanox® DDA, a diphenylamine derivative, isparticularly effective.

For the production of adhesives having optimum resistance to HClrelease, preferably 0.1 to 10 wt. %, more preferably 0.2 to 3 wt. % ofan antioxidant, preferably based on oligofunctional secondary aromaticamines (D3) or oligofunctional substituted phenols (D4), can be added,alone or in combination with 2 wt. % to 30 wt. % of a silica soldispersion (D2).

The composition according to the invention can additionally contain 0 to79.99 wt. % of further conventional adhesive auxiliary substances andadditives (E).

These are understood to be, for example, other polymers, such as e.g.polyacrylates, polyvinylidene chloride, polybutadiene, polyvinyl acetateand/or styrene-butadiene rubbers, which can preferably be added in theform of aqueous dispersions in a proportion of up to 30 wt. %, based onthe solids content of the composition. Such polymers can be used tomodify the properties of the adhesive compositions.

Further examples of adhesive auxiliary substances and additives (E) are,for example, fillers, such as silica flour, silica sand, barytes,calcium carbonate, chalk, dolomite or talc, optionally together withwetting agents, for example polyphosphates such as sodiumhexametaphosphate, naphthalene sulfonic acid, ammonium or sodiumpolyacrylic acid salts, the fillers being added in quantities ofpreferably up to 75 wt. %, more preferably 10 to 60 wt. %, even morepreferably 20 to 50 wt. %, and the wetting agents in quantities of 0.2to 0.6 wt. %, all figures being based on the solids content of thecomposition.

The amount of fillers added depends inter alia on whether thecompositions according to the invention are used as an adhesive orsealant. For use as an adhesive, maximum filler contents of around 30 to40 wt. % are preferred, based on the solids content of the composition.A content of polychloroprene particles of more than 40 wt. % ispreferred in this case.

For use as a sealant, maximum filler contents of around 60 to 75 wt. %are preferred, based on the solids content of the composition. A contentof polychloroprene particles of less than 40 wt. % is preferred in thiscase.

Further suitable auxiliary substances are, for example, organicthickeners, such as cellulose derivatives, alginates, starch, starchderivatives, polyurethane thickeners or polyacrylic acid, for use inquantities of around 0.01 to 1 wt. % based on the solids content, orinorganic thickeners, such as bentonite for example, for use inquantities of 0.05 to 5 wt. % based on the solids content.

For preservation purposes, fungicides can also be added to the adhesivecomposition according to the invention. These are used in quantities of0.02 to 1 wt. %, for example, based on non-volatile components. Suitablefungicides are for example phenol and cresol derivatives or organotincompounds.

Tackifying resins, such as e.g. unmodified or modified natural resinssuch as colophony esters, hydrocarbon resins or synthetic resins such asphthalate resins can optionally also be added in dispersed form to thepolymer dispersion according to the invention (see e.g. “Klebharze” R.Jordan, R. Hinterwaldner, p. 75-115, Hinterwaldner Verlag Munich 1994).Alkyl phenolic resin and terpene phenolic resin dispersions withsoftening points greater than 70° C., particularly preferably greaterthan 110° C., are preferred.

Plasticisers, such as those based on adipates, phthalates or phosphatesfor example, can also be added, for example in quantities of 0.5 to 10wt. % based on the solids content.

Based on the overall weight of the composition, the solids content ofthe composition according to the invention is preferably at least around50 wt. %, more preferably at least around 60 wt. %, even more preferablymore than 70 wt. %, corresponding to a content of volatile components inthe composition according to the invention of preferably less thanaround 50 wt. %, more preferably less than around 40 wt. %, even morepreferably less than around 30 wt. %.

Organic solvents, such as e.g. toluene, xylene, butyl acetate, methylethyl ketone, ethyl acetate, dioxane, triethanolamine, ethylene glycolor mixtures thereof can be included according to the invention in thecomposition. The organic solvents can be added to the water-containingcompositions according to the invention in small quantities of at mostaround 50 wt. %, based on the total amount of volatile components. Theyserve to improve adhesion to substrates that are difficult to bond, forexample.

To produce the compositions according to the invention, aqueousdispersions of components A), B) and optionally D1), D2), D3), D4) andE) are conveniently mixed together in the following proportions:

polychloroprene dispersion (A) 50 to 99.95 wt. % hydroxylamine (B) 0.05to 2 wt. % zinc oxide dispersion (D1) 0 to 10 wt. %. silicon dioxidedispersion (D2) 0 to 40 wt. % at least one antioxidant 0 to 10 wt. %differing from zinc oxide (D3, D4) other conventional adhesive 0 to79.95 wt. % auxiliary substances and additives (E)the stated percentages by weight referring in each case to the solidscontent of the composition, which adds up to 100%. (Unless otherwisespecified, the weights given below also relate to the solids content).The solids content denotes in this context the weight of non-volatilecomponents, such as in particular polychloroprene, ZnO and SiO₂. Thevolatile components include in particular also the high-boilingsolvents, which can be removed by distillation at up to 250°/15 torr.The solids content adds up to 100 wt. %. In addition, the antioxidant(D1) can be added in amounts of preferably 0 to 10 wt. %, preferably 0to 3 wt. %, based on the solids content of the composition.

The invention also provides a process for producing the compositionsaccording to the invention, characterised in that a hydrouspolychloroprene dispersion (A) is mixed with a hydrous hydroxylaminedispersion (B) or a water-soluble hydroxylamine, and a zinc oxidedispersion (D1) and/or a silicon dioxide dispersion (D2) and/orantioxidants (D3, D4) are optionally added and optionally furtherconventional adhesive auxiliary substances and additives (E) are alsoadded.

The compositions according to the invention can be used as adhesives oras sealants. Use as an adhesive is preferred.

The present invention therefore also provides the use of thehydroxylamine-containing polymer dispersions to produce adhesiveformulations, the adhesive formulations obtained in this way themselves,substrates coated with them and the polymer coatings obtained from thepolymer dispersions, and the substrates bonded together by means ofthese coatings.

According to DIN 16920, an adhesive is a non-metallic substance that canbond together adherends by surface bonding (adhesion) and inner strength(cohesion).

Adhesive formulations according to the invention can be applied in knownways, for example by spreading, pouring, knife application, spraying,roller application or dipping. The adhesive film can be dried at roomtemperature or at elevated temperature.

Application is preferably by means of the spray process, as describedfor example in EP-A 0 624 634.

The adhesives according to the invention are used for example forbonding any substrates of like or unlike nature, such as wood, paper,plastics, textiles, leather, rubber or inorganic materials such asceramics, earthenware, fibreglass or cement, but also for impregnating,coating and laminating fabric and paper, as a binder for fibres or toreinforce toe caps on shoes and as an insulating material.

EXAMPLES

A Substances Used

TABLE 1 Polychloroprene dispersion Dispersion Polychloroprene typeManufacturer Dispercoll ® C 84 pH 12, highly crystallising, gel- Bayerfree, solids content 55 +/− 0.5% MaterialScience Chloroprene homopolymerAG, DE

The average particle diameter of the polychloroprene particles was 95nm.

TABLE 2 N,N-Diethyl hydroxylamine (DEHA) Product Supplier Delivery formN,N-Diethyl Borchers GmbH, Langenfeld, Aqueous solution, 85%hydroxylamine DE

TABLE 3 Additives and auxiliary substances Solids Product contentFunction Manufacturer Borchers ® VP 9802 50% Stabiliser Borchers GmbH,(zinc oxide dispersion Langenfeld, DE not according to the invention)Rhenofit ® DDA-50 EM 50% Antioxidant Rhein Chemie (diphenylamine GmbH,Mannheim, derivative dispersion) DE Nano zinc oxide Zinc oxideStabiliser Bayer AG, DE dispersion A (see below) 15% Dispercoll ® S 303030% Stabiliser Bayer AG, DE silica sol Dermulsene ® TR 93 50% Resin DRT,Cedex, FR (terpene phenolic resin dispersion)Borchers® VP 9802:

Aqueous zinc oxide dispersion with a particle size of 50,000 to 150,000nm.

Dispercoll® S 3030:

Silica gel with a specific surface area of 300 (m²/g) and an averageparticle diameter of approx. 9 nm.

B Production of the Nano Zinc Oxide Dispersion A Used

The nano zinc oxide dispersion A is produced by the process described inWO 00/50503 (example 1: production of a zinc oxide gel in methanol fromzinc acetate dihydrate). Production of the zinc oxide sol from the zincoxide gel takes place in an analogous manner to example 7 in thispublication, the zinc oxide gel being mixed only with water andtriethanolamine and the methanol component being drawn off under vacuum,such that a nano zinc oxide dispersion in triethanol/water is obtained.The average primary particle size is 10.5 nm (number average), the zincoxide content 15%.

C Measurement Techniques

C1: Determination of Thermal Stability (HCl Stability)

The dried adhesive specimens are tested in accordance with DIN 53381,method B.

Method of Measuring:

Measuring instrument: 763 PVC Thermomat supplied by Metrohm, CH-9101Herisau, Switzerland

The specimens (thickness 0.1 to 1 mm) are cut to an edge length ofapprox. 2 to 3 mm, 0.2 g are weighed into a test tube and themeasurement is performed at 180° C. with air as the carrier gas. Theelectrical resistance of water, in which the HCl gas that is formeddissolves again, is measured. The time at which the electricalresistance reaches the value of 50 μS/cm is stated as the HCl stability.The higher the value, the more stable the measured specimen with regardto HCl release.

D Results:

D1: Determination of Storage Stability (Change in pH)

2 g of diethyl hydroxylamine are added to 100 g of polychloroprenedispersion whilst stirring and the dispersion is stored at 60° C. Aftera storage period of 7 and 14 days the pH is determined.

TABLE 4 Stabilisation of pH No. 1 2*) Solids content in wt. % ¹⁾Dispercoll ® C 84 100 100 55 Diethyl hydroxylamine — 5 20 pH ofdispersion: Immediately 13.3 13.3 After 7 days at 60° C. 9.9 10.9 After14 days at 60° C. 9.4 10.3 *)Example according to the invention (¹⁾Parts by weight of dispersion)D2: Thermal Stability of a Formulation Using Various Zinc OxideDispersions and Replacing the Antioxidant Rhenofit® DDA with DEHA

TABLE 5 HCl stability of dispersions No. Solids 3 4*) 5 6*) content ¹⁾Dispercoll ® C 84 1000 1000 1000 1000 55 wt. % Rhenofit ® DDA 20 20 50wt. % 50 EM Borchers ® VP 9802 5.3 5.3 50 wt. % Nano zinc oxide A — 1.71.7 15 wt. % DEHA 50 50 20 wt. % Dermulsene ® TR 93 300 300 300 300 50wt. % HCl stability in 40 385 85 350 minutes (¹⁾ Parts by weight ofdispersion)D3: Influence of N,N-Diethyl Hydroxylamine (DEHA) and Nano SiliconDioxide on the HCl Stability of Dispercoll® C Formulations

TABLE 6 HCl stability of dispersions No. Solids 7 8 9 10 11*) 12*) 13*)14*) content ¹⁾ (wt. %) Dispercoll ® C 84 182.6 182.6 182.6 182.6 182.6182.6 182.6 182.6 58 DEHA — — — — 5.0 5.0 5.0 5.0 20 Dispercoll ® S3030— 87.8 87.8 — 87.8 — 87.8 30 Rhenofit ® DDA 2.9 2.9 2.9 2.9 2.9 2.9 2.92.9 50 Nano ZnO **) — — 24 24 — — 24 24 15 HCl stab, (min) 87 240 520380 105 270 590 693 *)Example according to the invention (¹⁾ Parts byweight of dispersion) **) Based on zinc oxide content

Formulations 7 to 10 correspond to formulations 11 to 14, except thatthe latter contain a hydroxylamine derivative according to theinvention. If formulation 7 is compared with 11, 8 with 12, 9 with 13and 10 with 14, it can be seen in all comparisons that in the case ofthe formulations containing hydroxylamine, HCl development issignificantly delayed, i.e. the addition of the hydroxylamine derivativehas a stabilising effect.

1. Aqueous polymer dispersion free from residual monomer and comprising:(A) polychloroprene particles and (B) N,N-diethyl hydroxylamine and/orN-isopropyl hydroxylamine, wherein the amount of N,N-diethylhydroxylamine and/or N-isopropyl hydroxylamine is 0.05 to 2 wt. % of thesolid content of the dispersion.
 2. Aqueous polymer dispersion accordingto claim 1, wherein the amount of N,N-diethyl hydroxylamine and/orN-isopropyl hydroxylamine is 0.1 to 1.0 wt. % of the solid content ofthe dispersion.
 3. Adhesive and sealant formulations containing aqueouspolymer dispersions according to claim
 1. 4. Substrates coated withadhesive formulations according to claim
 3. 5. Polymer coatings obtainedfrom aqueous polymer dispersions according to claim
 1. 6. Substratesbonded together with the adhesive and sealant formulations according toclaim
 5. 7. A process for preparing an aqueous polychloroprenedispersion comprising the steps of (1) polymerizing chloroprene; (2)removing residual monomers and other volatile constituents bydistillation; and (3) adding N,N-diethyl hydroxylamine and/orN-isopropyl hydroxylamine, wherein the amount of N,N-diethylhydroxylamine and/or N-isopropyl hydroxylamine is 0.05 to 2 wt. % of thesolid content of the dispersion.